static void assert_ivec(const ivec &expected, const ivec &actual) { ASSERT_EQ(expected.length(), actual.length()); for (int n = 0; n < expected.length(); ++n) { ASSERT_EQ(expected[n], actual[n]); } }
void cofdm_map::set_data(ivec x) { cvec qv; bvec ce; int K = x.length(); int i; ce.set_length(K); ce.ones(); #if (DEBUG_LEVEL == 3) cout << "***** cofdm_map::set_data *****" << endl; cout << "K=" << K << endl; cout << "ce=" << ce << endl; cout << "x=" << x << endl; cout << "data_carriers=" << data_carriers << endl; #endif if( K == data_carriers.length() ) { qv = qammod.process(ce,x); #if (DEBUG_LEVEL == 3) cout << "qv=" << qv << endl; #endif for (i=0; i<K; i++) { y0(data_carriers(i))=qv(i); } } else { throw sci_exception("cofdm_map::set_data - x.size() <> data_carriers.size()=", data_carriers.length()); } #if (DEBUG_LEVEL == 3) cout << "y0(piltos) y0(zeros) migh have rubbish" << endl; cout << "y0=" << y0 << endl; cout << "+++++ cofdm_map::set_data +++++" << endl; #endif }
void gfx::set(int qvalue, const ivec &invalues) { // it_assert0(qvalue>0, "gfx::set, out of range"); degree=invalues.length()-1; coeffs.set_size(degree+1); for (int i=0;i<degree+1;i++) coeffs[i].set(qvalue,invalues[i]); q=qvalue; }
cvec qam_mod::process(bvec ce, ivec x) { cvec y; int N; ivec iv; cvec cv; #if (DEBUG_LEVEL==3) cout << "***** qam_mod::process *****" << endl; cout << "ce=" << ce << endl; cout << "x=" << x << endl; sleep(1000); #endif iv.set_length(1); cv.set_length(1); N=ce.length(); y.set_length(N); if (x.length()!=N) { throw sci_exception("qam_mod::process - ce.size <> x.size", x.length() ); } for (int i=0; i<N; i++) { if ( bool(ce[i])) { iv[0] = x[i]; cv = modulate(iv); y0 = scale * cv[0]; } y[i]=y0; } #if (DEBUG_LEVEL==3) cout << "y=" << y << endl; cout << "+++++ qam_mod::process +++++" << endl; sleep(1000); #endif return (y); }
bmat int2bin::process(bvec ce, ivec x) { bmat y; int N; #if (DEBUG_LEVEL==3) cout << "***** int2bin::process *****" << endl; cout << "ce=" << ce << endl; cout << "x=" << x << endl; sleep(1000); #endif N=ce.length(); if (x.length()!=N) { throw sci_exception("int2bin::process - ce.size <> x.rows()", x.length() ); } y.set_size(N,symbol_size); for (int i=0; i<N; i++) { if ( bool(ce[i])) { y0 = dec2bin(symbol_size, x[i]); if (! msb_first) { y0 = reverse(y0); } } y.set_row(i,y0); } #if (DEBUG_LEVEL==3) cout << "y=" << y << endl; cout << "+++++ int2bin::process +++++" << endl; sleep(1000); #endif return (y); }
void cofdm_sel::set_sel_carriers(ivec cindx) { if( cindx.length() < NFFT ) { if (itpp::min(cindx) >= 0) { if (itpp::max(cindx) < NFFT) { sel_carriers = cindx; } else { throw sci_exception("cofdm_sel::set_sel_carriers - max(cindx) > NFFT=", NFFT); } } else { throw sci_exception("cofdm_sel::set_sel_carriers - min(cindx) < 0 "); } } else { throw sci_exception("cofdm_sel::set_sel_carriers - bad cindx.size() > NFFT=", NFFT); } }
void cofdm_map::set_pilots_carriers(ivec pcindx) { if( pcindx.length() < NFFT ) { if (itpp::min(pcindx) >= 0) { if (itpp::max(pcindx) < NFFT) { pilots_carriers = pcindx; } else { throw sci_exception("cofdm_map::set_pilots_carriers - max(pcindx) > NFFT=", NFFT); } } else { throw sci_exception("cofdm_map::set_pilots_carriers - min(dcindx) < 0 "); } } else { throw sci_exception("cofdm_map::set_pilots_carriers - bad pcindx.size() > NFFT=", NFFT); } }
void cofdm_map::set_zero_carriers(ivec zcindx) { if( zcindx.length() < NFFT ) { if (itpp::min(zcindx) >= 0) { if (itpp::max(zcindx) < NFFT) { zero_carriers = zcindx; } else { throw sci_exception("cofdm_map::set_zero_carriers - max(zcindx) > NFFT=", NFFT); } } else { throw sci_exception("cofdm_map::set_zero_carriers - min(zcindx) < 0 "); } } else { throw sci_exception("cofdm_map::set_zero_carriers - bad zcindx.size() > NFFT=", NFFT); } }
void cofdm_map::set_data_carriers(ivec dcindx) { if( dcindx.length() < NFFT ) { if (itpp::min(dcindx) >= 0) { if (itpp::max(dcindx) < NFFT) { data_carriers = dcindx; } else { throw sci_exception("cofdm_map::set_data_carriers - max(dcindx) > NFFT=", NFFT); } } else { throw sci_exception("cofdm_map::set_data_carriers - min(dcindx) < 0 "); } } else { throw sci_exception("cofdm_map::set_data_carriers - bad dcindx.size() > NFFT=", NFFT); } }
bool Reed_Solomon::decode(const bvec &coded_bits, const ivec &erasure_positions, bvec &decoded_message, bvec &cw_isvalid) { bool decoderfailure, no_dec_failure; int j, i, kk, l, L, foundzeros, iterations = floor_i(static_cast<double>(coded_bits.length()) / (n * m)); bvec mbit(m * k); decoded_message.set_size(iterations * k * m, false); cw_isvalid.set_length(iterations); GFX rx(q, n - 1), cx(q, n - 1), mx(q, k - 1), ex(q, n - 1), S(q, 2 * t), Xi(q, 2 * t), Gamma(q), Lambda(q), Psiprime(q), OldLambda(q), T(q), Omega(q); GFX dummy(q), One(q, (char*)"0"), Omegatemp(q); GF delta(q), tempsum(q), rtemp(q), temp(q), Xk(q), Xkinv(q); ivec errorpos; if ( erasure_positions.length() ) { it_assert(max(erasure_positions) < iterations*n, "Reed_Solomon::decode: erasure position is invalid."); } no_dec_failure = true; for (i = 0; i < iterations; i++) { decoderfailure = false; //Fix the received polynomial r(x) for (j = 0; j < n; j++) { rtemp.set(q, coded_bits.mid(i * n * m + j * m, m)); rx[j] = rtemp; } // Fix the Erasure polynomial Gamma(x) // and replace erased coordinates with zeros rtemp.set(q, -1); ivec alphapow = - ones_i(2); Gamma = One; for (j = 0; j < erasure_positions.length(); j++) { rx[erasure_positions(j)] = rtemp; alphapow(1) = erasure_positions(j); Gamma *= (One - GFX(q, alphapow)); } //Fix the syndrome polynomial S(x). S.clear(); for (j = 1; j <= 2 * t; j++) { S[j] = rx(GF(q, b + j - 1)); } // calculate the modified syndrome polynomial Xi(x) = Gamma * (1+S) - 1 Xi = Gamma * (One + S) - One; // Apply Berlekam-Massey algorithm if (Xi.get_true_degree() >= 1) { //Errors in the received word // Iterate to find Lambda(x), which hold all error locations kk = 0; Lambda = One; L = 0; T = GFX(q, (char*)"-1 0"); while (kk < 2 * t) { kk = kk + 1; tempsum = GF(q, -1); for (l = 1; l <= L; l++) { tempsum += Lambda[l] * Xi[kk - l]; } delta = Xi[kk] - tempsum; if (delta != GF(q, -1)) { OldLambda = Lambda; Lambda -= delta * T; if (2 * L < kk) { L = kk - L; T = OldLambda / delta; } } T = GFX(q, (char*)"-1 0") * T; } // Find the zeros to Lambda(x) errorpos.set_size(Lambda.get_true_degree()); foundzeros = 0; for (j = q - 2; j >= 0; j--) { if (Lambda(GF(q, j)) == GF(q, -1)) { errorpos(foundzeros) = (n - j) % n; foundzeros += 1; if (foundzeros >= Lambda.get_true_degree()) { break; } } } if (foundzeros != Lambda.get_true_degree()) { decoderfailure = true; } else { // Forney algorithm... //Compute Omega(x) using the key equation for RS-decoding Omega.set_degree(2 * t); Omegatemp = Lambda * (One + Xi); for (j = 0; j <= 2 * t; j++) { Omega[j] = Omegatemp[j]; } //Find the error/erasure magnitude polynomial by treating them the same Psiprime = formal_derivate(Lambda*Gamma); errorpos = concat(errorpos, erasure_positions); ex.clear(); for (j = 0; j < errorpos.length(); j++) { Xk = GF(q, errorpos(j)); Xkinv = GF(q, 0) / Xk; // we calculate ex = - error polynomial, in order to avoid the // subtraction when recunstructing the corrected codeword ex[errorpos(j)] = (Xk * Omega(Xkinv)) / Psiprime(Xkinv); if (b != 1) { // non-narrow-sense code needs corrected error magnitudes int correction_exp = ( errorpos(j)*(1-b) ) % n; ex[errorpos(j)] *= GF(q, correction_exp + ( (correction_exp < 0) ? n : 0 )); } } //Reconstruct the corrected codeword. // instead of subtracting the error/erasures, we calculated // the negative error with 'ex' above cx = rx + ex; //Code word validation S.clear(); for (j = 1; j <= 2 * t; j++) { S[j] = cx(GF(q, b + j - 1)); } if (S.get_true_degree() >= 1) { decoderfailure = true; } } } else { cx = rx; decoderfailure = false; } //Find the message polynomial mbit.clear(); if (decoderfailure == false) { if (cx.get_true_degree() >= 1) { // A nonzero codeword was transmitted if (systematic) { for (j = 0; j < k; j++) { mx[j] = cx[j]; } } else { mx = divgfx(cx, g); } for (j = 0; j <= mx.get_true_degree(); j++) { mbit.replace_mid(j * m, mx[j].get_vectorspace()); } } } else { //Decoder failure. // for a systematic code it is better to extract the undecoded message // from the received code word, i.e. obtaining a bit error // prob. p_b << 1/2, than setting all-zero (p_b = 1/2) if (systematic) { mbit = coded_bits.mid(i * n * m, k * m); } else { mbit = zeros_b(k); } no_dec_failure = false; } decoded_message.replace_mid(i * m * k, mbit); cw_isvalid(i) = (!decoderfailure); } return no_dec_failure; }
/* Return the mean value of the elements in the vector */ double mean(const ivec& v) { return (double)sum(v)/v.length(); }